Technical Field
This disclosure relates to a camera system, and more specifically, to a camera system with multiple lenses configured to manipulate electronic rolling shutter (“ERS”) exposure timing during image capture.
Description of the Related Art
An imaging system typically consists of an imaging lens and an image sensor. An imaging lens collects light emitted or reflected from objects in a scene and directs collected light upon the image sensor. An image sensor is a photosensitive device that converts light incident upon the image sensor during an image capture to an electronic signal representative of the captured light. To obtain color image data, a color filter array (such as a Bayer filter) is used in conjunction with the image sensor to separate between different spectral regions of the total light spectrum of the image being captured. Color filter arrays separate captured light into (for instance) green image planes, red image planes, and blue image planes.
Given an image sensor's active area dimension (the image sensor's “format”) and the desired field of view, the focal length of a lens can be calculated. The size of the aperture of the lens can be set according to image sensor's photo sensitivity, exposure time, and noise level tolerance. The focal length divided by the aperture's size is called the “F-number,” and indicates the ability of the lens to collect light. Lower F-Numbers are associated with more light being collected by the lens and directed upon the image sensor.
A phenomena caused by the use of color filter arrays is the appearance of color artifacts also caused by the spatial disposition of the different colors. For example, in a captured image of a white line 1 pixel deep on a black background, the white line will appear in various colors depending on the position of the light from the line incident upon the image sensor. Multi-lens systems can be implemented to reduce such artifacts, but can be accompanied by issues of increased system cost and complexity. A typical CMOS image sensor can allow a camera system to expose, for each of a plurality of rows of pixels, the row of pixels for a period of time (the “exposure time”).